Regulating means



H. MCC. WEIR REGULATING MEANS Feb. 10, 1942.

Filed Feb. 23, 1959 Fi' 2 30 Fg ATTORNEYS Patented y Feb. l0, 1942 REGULATING MEANS Horace McColloch Weir, Philadelphia, Pa., assignor, by mesne assignments, to Maschinenund Metallwaren-Handelsgesellschaft m. b. H., Berlin, Germany, a limited-liability company of Germany Application February 23, 1939, Serial No. 257,785

A In Germany February 28, 1938 1 claim. (o1. zoe-16o) 'rms invention 'rentes to improvements m distillation or reiining processes, and refers more particularly to a method and means for regulating the amount of heat supplied to a distillation or rectification column.

In a distillation or rectification plant, it is customary to heat a portion of the distillation liquid The head portion .'of' the column usually contains a condenser wherein the distillation liquid is precipitated. A small part of the precipitated liquid is removed from the column, while the greater portionof the precipitated liquid ows back to the bottom of the column and is again brought into contact with the heated vapors of the distillation liquid. A part of the liquid reaching the bottom of the column is permanently removed therefrom, whileanother part. as already stated, is heated to form a vapor which is returned to the column. l The proper operation of the column depends primarily upon the maintenance of a Iconstant pressure and temperature and the regulation of the supply of the raw product and of the removal of the liquid at the head and bottom of the co1- umn. When these requirements are vcomplied with, the proper operation of the distillation co1- umn depends substantially solely upon the amount of liquid flowing from the head portion of the c olumn back to the bottom thereof, i. e., from the so-called return ilow ratio.

If predetermined amounts of the liquid are supplied to the ycolumn and are removed therefrom at'the head and the bottom of the column,v

then a predetermined amount of heat is necessary fo-' the heating of the liquid flowing through The objects of the present invention may be realized by adapting the supplied amounts of heat to the particular requirements in the column through the provision of a regulatable heat ex- In prior art the exact regulation of this amount I of heat was very difiicult, particularly since the columns are usually quite high and since there are small differences in temperature and pressure between the individual plates or filters of the column.

It is an object of the present invention to avoid. these drawbacks and to provide a distillation and rectification plant wherein the amount of sup- Other objects of4 the present invention will be apparent in the course of the followingspecifica-f tion. v v

changer wherein the liquid removed from the bottom of the column is brought in contact with indirect heat exchanging surfaces which are 'heated partly by steam, preferably under a high pressure, and partly by the condensate of that steam.

As is Well known, steam contacting the same area ,as its condensate transmits much greater amounts of heat in equal periods of time than the condensate. By shifting the dividing linebetween a steam chamber and a condensed water chamber in the heat exchanger, i. e. by varying the amount of heat supplied by steam in relation to the amount of heat supplied by the condensate, Athe total amount of supplied heat per unit of time may be precisely and -exactly regulated.

The invention will appear more clearly from the following detailed description when taken in connection with the laccompanying drawing showing by way of example a preferred embodiment of the inventive idea.

In the drawing: T

Figure 1 illustrates diagrammatically, partly in side elevation and partly in vertical section, a

distillation plant constructed in accordance with the principles of 'the present invention, the co1- umn for conveniencesake being -drawn on a much smaller scale than the other parts of the plant.

Figure 2 is ya section along the line 2-2 of Figure l.

The 'plant shown in the drawing comprises a column I provided with a plurality of lter oors or plates 2 of the usual typ@-v A pipe 3 is used for introducing the raw product which is to be distilled, substantially into the middle of the co1- umn I.

VThe head 4 of the column Iv contains a con denser 5 which is cooled by any suitable means, for instance, vby -water circulating through the pipes 6 rand The liquid precipitated by the condenser v5 flows through the pipe 8 to a centrifuge 9 or any other suitable separating device.

f A pipe Il! is used for withdrawing a part ofthe pipe II is used for returning the remaining portion of the liquid to the column I.

A suitable regulating device I2 which may have the Vform of an overflow weir is situated close to th'e lbottoni I3 of the columnand is connected l with a pipe Il through which the liquid 2D at the bottom of the column may be removed from circulation. The amount of the removed liquid may be regulated by Vimpulse-steering means (not slxown).

A part of the liquid which is collected at the bottom of the column I iiows through a pipe l Ito a heating device i6 the interior of which contains vertical pipes I7.

The upper. portion of the heat exchanger I8 is connected by the pipe I8 with the column I, so that a duid can pass from the pipes I1 back to the column l.

The liquid flowing from the column I into the heat exchanger I6 is heated therein by steam, which is introduced into the interior of the heat exchanger I6 under high pressure through the pipe I 9. Condensed water resulting from the heat exchange between the steam and the liquid 2li ows through the pipe 2| into a flow regulator 22 having the form of a cylinder provided with a bottom portion 23 cars rying a stuing box 24. Y

A pipe 25 projects into the interior of the cylinder 22 and is enclosed by the stuiing box 24, so that the cylinder 22 remains liquid-tight. 'Ihe condensed water 3G may leave the cylinder 22 only through the pipe 25, and the position of the upper edges 26 of the pipe 25 determines the level of the condensed water 3U within the cylinder 22 and the heater I6.

The pipe 25 which is connected to a steam trap 25a, may be moved within the cylinder 22, whenever necessary, either manually or by any suitable mechanical means, for example, by a rack 2B attached to the pipe 25 and a ratchet wheel 29 drivenby any suitable motor.

The device is operated as follows:

The circulation of-the substance to be distilled is carried out in the customary manner.

Both liquid and vapor in intimate admixture pass into the column I through the pipe I8.

The heating of the substance which flows in the form of a liquid 20 from' the bottom I3 of the column I through the pipe I5 and which is reintroduced in the form of a vapor into the column I through the pipe I8 is carried out in accordance with the following principles:

It is well known that the owlng heated steam gives up a much larger amount of heat to heat exchange surfaces per time and surface units than hot water. Therefore, the amount of heat supplied to the liquid. 20 can be easily adjusted by varying the ratio of the heat exchange surfaces ,which are contacted by steam to the heat exchange surfaceswhich are contacted by the condensed water. Furthermore, this ratio is equal to the ratio between the heights of the steam chamber and the condensed water chamber in the heat exchanger I6, these heights being represented by the reference characters hn and hw in the drawing, so that the ratio is equal to If the steam chamber, i. e., if hn is great, then considerable amounts of the liquid 20 will be evaporated within the container II and a large amount of liquid and vapor will'owthrough the pipe I8 into the column l. 0n the other hand, if the steam chamber is small, that is, if hw .is large, the amount of the evaporated liquid is small, so that only a small amount of the evaporated distillate flows through the pipe I8 into the column I.

Thus, it is obvious that the return ilow ratio with which the column I operates is primarily determined by the amount of supplied heat and 1 to the other chamber, a portion of the steam i secondarily by those imaginary surfaces which separate the steam chambers from the condensed water chambers in the heat exchanger I6.

The relative volumes of the steam chamber and the condensed water chamber may be conveniently adjusted by moving the pipe 25 within the cylinder 22.

The pipe 25 Vmay be moved by hand, mechanically, or automatically.

Hand adjustment, for instance, by means of a hand wheel and a threaded rod l(not shown) is advantageously employed when changes in the composition of the raw product supplied through the pipe 3 occur only at infrequent intervals and when it is possible to maintain the pressure, and consequently the temperature, of the heating steam substantially constant and when, furthermore, the compositions for the distillate and the residueproduct are not to be changed frequently.

0n the other hand, if the operation of the plant is of a diilcult or complicated nature, then the position of the pipe 25, and consequently the position of the surfaces separating the steam chambers from the water chambers, and the ratio hnrhw may be changed automatically by the use of measuring instruments which respond to certain operative data in the column I and which transmit their impulses by any suitable means not shown in the drawing to the pipe 25. It is possible to cause the temperature or pressure at certain parts'of the column I to iniiuence measuring instruments situated therein winch then cause movement of the pipe 25 in the described manner, or it is possible to utilize for that purpose the amount of the supplied liquid or of the withdrawn liquid or various physical or 'chemical properties of the iluids ilowing to and steam ilows around these pipes, the reverse procedure may be used, namely, steam may be caused to circulate through the inner pipes I1 andthe liquid 20 maybe caused to flow through the enclosing chambers. In general, any; suitable heating vdevice may be used for the same purposes. The regulating device 22 may be also differently constructed. All of these and other modications and variations are to be included within the scope of the present invention.

What is claimed is:

A device for regulating heat supplied to a distillation or rectification column, said device oomprising, in combination with the distillation or rectiiication' column, a heat exchanger having at least two separate heat transmitting chambers in juxtaposition and heat exchange relationship with each other, means connected with said heat exchanger and with -the bottom of said column for introducing a distillation liquid from the bottom of said column into one,of said chambers, means connected with said heat exchanger and said column for removing vapors of said distillation liquid from that chamber and into said column, means connected with Athe top portion of said heat exchanger for introducing steam inbeing condensed therein by heat exchange with said distillation liquid, a flow regulator casing,

'steam from said heat exchanger into said ow regulator casing, means connected with the top portion of said heat exchanger and said flow regulator casing to equalize steam pressures r, therein, a vertical pipe movable within said ow regulator casing for varying the level of the condensate of said steam in said flow regulator casing and said heat exchanger, said pipe precluding the passage of steam `therethrough, and

5 means connected with said pipe for moving the same to vary the eective heat exchange surface.

HORACE MCCOLLOCH WEIR. 

